How to check and remuve my Apple credit balance

From: Check your Apple ID balance - Check your Apple Account balance - Apple Support -->

"About unused Apple ID balance

You can't redeem or return Apple Gift Cards, App Store & iTunes Gift Cards, or unused Apple ID balance for cash, except as required by law. If your jurisdiction allows for refund of redeemed gift balances, you can contact Apple Support." Read the support article for more details.

The above excerpt only mentions balances from gift cards as being eligible for refunding, and only in limited places where laws may require that. Read the support article for more details.

Apart from spending it, in Apple's support article Change your Apple ID country or region - Apple Support Apple lists only a single other way to do this:

"If you still can't change your country or region, or you have less store credit than the cost of a single item, contact Apple Support". Apple offers this specific link for that service --> https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0998&symptom_id=20198

Apple will remove the balance and keep it.

In the interest of full disclosure here's an additional method to "zero" account balance. Since Apple does not include it in the support article Change your Apple ID country or region - Apple Support I am posting it separately.

+ "Spend any balance remaining on your Apple ID"

If you find your store credit is less than the cost of a single item and you still have a valid payment method for your old country such as a credit card, you can use the payment method to make up the difference in the cost of an item ( How apps, content, and subscriptions from Apple are billed - Apple Support ). Perhaps buy something such as a music track which you can download and also keep a backup copy. Remember that anything purchased may not be available for re-download in another country but as long as you have your own copy you will always have it.

This method—where you get to use your balance by spending it instead of giving it to Apple—used to be in Apple's support article about changing countries, but a few years ago Apple stopped mentioning it even though it is still perfectly effective.